Permeants are any of a wide variety of materials which perform useful functions by distributing themselves via physical and/or chemical transport mechanisms, such as diffusion, evaporation or the like, throughout a host medium, such as a gas, liquid, solid or combination thereof. Some examples of permeant materials which find wide use in industrial, commercial, domestic and medical applications are perfumes, disinfectants, foods, pharmaceuticals, flavors, insecticides, insect repellents, cleansing and cleaning materials, preservatives, emollients, exipients, stabilizers, dyes, diluents, lotions, inhalants, fungicides, air fresheners, anti-static agents, corrosion inhibitors, fertilizers, enzymes, poisons and lures.
It is well known to entrap permeants in bulk polymers or microcapsules to attain controlled/sustained release of the permeant. Examples may be found in U.S. Pat. Nos. 2,007,721, 2,467,583, 3,041,289, 3,047,431, 3,140,184, 3,400,093, 3,528,819, 3,551,556, 3,577,512, 3,618,604, 3,626,940, 3,630,200, 3,641,237, 3,660,071, 3,689,634, 3,761,286, 3,857,964, 3,868,447, 3,872,023, 3,881,026, 3,886,125, 3,939,099, 3,941,858, 4,003,846, 4,009,684, 4,010,038, 4,011,311, 4,066,387, 4,089,800, 4,110,261, 4,125,370, 4,145,184, 4,206,301, 4,226,944, 4,230,687, 4,257,176, 4,269,729, 4,275,194, 4,277,364, 4,309,509, 4,310,397, 4,321,252, 4,328,119, 4,339,356, 4,344,857, 4,344,857, 4,350,774, 4,356,115, 4,380,552, 4,380,626, 4,381,066, 4,382,813, 4,386,108, 4,386,193, 4,391,717, 4,401,456, 4,401,456, 4,407,795, 4,409,201, 4,413,843, 4,423,091, 4,423,099, 4,434,086, 4,435,383, 4,439,488, 4,439,488, 4,446,032, 4,456,587, 4,462,880, 4,515,909, 4,521,541, 4,522,953, 4,524,068, 4,525,520, 4,540,721, 4,542,162, 4,543,367, 4,552,693, 4,555,438, 4,555,504, 4,557,929, 4,565,807, 4,569,852, 4,580,581, 4,582,635, 4,587,129, 4,598,070, 4,603,123, 4,618,629, 4,629,621, 4,634,614, 4,649,082, 4,650,898 and 4,663,316.
At present, one of the commercially popular applications of microencapsulation technology is encapsulation of fragrances to form microcapsules that are distributed on a paper substrate for use as advertising matter in the form of magazine inserts, blotters and the like. A number of problems have been encountered in this field, including premature/excessive release of the fragrance or portions thereof. Also, this technology could achieve wider commerical utilization if it could be performed more economically with more effective and controllable entrapment. Optionally, the technology could achieve wider utilization if it could be successfully applied to water-soluble or hydrophilic water-insoluble permeants which heretofore have been at least difficult if not impossible to encapsulate successfully. This invention, among other things, provides solutions to these needs.